钢铁钒钛

Study on Promoting Low-temperature Fast Reaction by Mechanical Force

Zhao Pei, Guo Peimin, Zhang Dianwei

2007, 28(2): 1-5.

Abstract(20) PDF(1)

Abstract:
Physical and chemical properties of iron ore powder and carbon powder with mechanical impact are studied.During milling,the particle and grain sizes of iron ore and carbon are gradually refined,and the specific surface area is continuously increased.Amorphism,or phase change can occur when iron ore powder and carbon powder are refined further.Distortion and dislocation occur during grain refining process,which form a lot of activation center with decrease of activation energy of reactions.Gradual increase of specific surface area also improves reactivity of powder,and promotes gas-solid reaction and solid-solid reaction.Reduction temperature of refined iron ore powder is about 300℃ less than that of coarse powder,and will be reduced further with addition of catalyst.

Synthesizing VO_2-xN_y Thin Films by Microwave Plasma Enhanced Processes

Chen Jinmin, Huang Zhiliang, Liu Yu, Wang Shenggao

2007, 28(2): 6-8,26.

Abstract(22) PDF(1)

Abstract:
According to the character of VO₂ taking phase transition at near 68℃,using the mixture gas of high pure hydrogen and high pure nitrogen as precursor,VO_2-xN_y thin films are synthesized at low temperature by microwave plasma enhanced procesesses using V₂O₅ as molecular precursors through coating film on glass slice.The components of synthesized samples are characterized by X-ray diffraction(XRD),the X-ray diffraction pattern indicates that the synthesized samples are nitrogen doped VO_2-xN_y,the crystallinity of synthesized sample is low and the particle size is small.The measurement of phase transition temperature indicates that the phase transition temperature of VO_2-xN_y thin films is dropped due to doped nitrogen,the lowest phase transition temperature is 42℃.

Effects of Titanium Microalloying on Microstructure and Properties of Rephosphorized Steel Sheet

Zheng Zhiwang

2007, 28(2): 9-15.

Abstract(22) PDF(1)

Abstract:
The effects of 0.015% titanium microalloying on the microstructure and properties of rephosphorized steel sheet were investigated by analyzing its microstructure and properties as hot-rolled and as annealed as well as its recrystallization dynamic behavior during annealing under different coiling temperatures (600,650 and 700℃ separately).The results showed that the microstructure and properties of the rephosphorized steel sheet were little affected by the hot-rolling coiling temperature whereas its recrystallization dynamics was prohibited after titanium microalloying,especially coiling at 600℃.It was also found that not only the strength of as hot-rolled or as annealed was increased after titanium microalloying,but also the mechanical properties became more sensitive to coiling temperature and annealing temperature.As a result,both the as hot-rolled and the as annealed strength of the Ti treated rephosphorized steel sheet were increased as the coiling temperature or the annealing temperature was lowered. The effect of titanium on the microstructure and properties of the rephosphorized steel was related to the coarsening of titanium precipitates.

Physical Simulation and Optimization of Submerged Entry Nozzle Used for Rectangular Bloom

Diao Jiang, Xie Bing, Li Yugang, Li Gang, Qi Fei

2007, 28(2): 16-20.

Abstract(18) PDF(2)

Abstract:
In order to solve the problems of slag inclusion,bulging and sticker breakout on the 165 mm×280 mm rectangular bloom in a steel work,the structure forms of submerged nozzle and processing parameters are optimized by means of simulating experiment.The optimization of parameter includes submerged depth of the nozzle,tilted angle of the nozzle port,and area ratio of nozzle port and nozzle section.The results of the simulation experiment show that various nozzle parameters have different effect on the fluid flow behaviour.The single outlet SEN used at present is the sticking point of problem in production process.A two side outlet SEN 9^# and a four side outlet SEN 42^# adapted to 165mm×280mm rectangular bloom are optimized.

Study on Precipitates of V-N Microalloyed CSP Steel

Pan Tao, Yang Caifu, Mao Xinping, Zhang Yongquan, Liu Qingyou

2007, 28(2): 21-26.

Abstract(14) PDF(2)

Abstract:
A Gleeble 1500D simulation machine is applied to simulate the production process of V-N microalloyed CSP steel strip in laboratory.The results show that almost all Ti of the steel precipitates as TiN in the incipient period of continuous casting.With the temperature decreasing of casting slab,V starts to precipitate with TiN as nucleation core or nucleate and grow up independently.After soaking,most of the independently-nucleated V(C,N) tends to dissolve,and the undissolved V(C,N) starts to grow up,meanwhile the V in (Ti,V)(C,N) dissolve partially and the V content in these particles reduces.During the tandem rolling process,the V(C,N) precipitates from the steel again,which plays a role of preventing austenite grain from growing up and facilitates ferrite nucleation.This increases austenite/ferrite transformation ratio and fines ferrite grain size eventually.

Effect of Rolling Schedule on Section Inhomogeneity of Heavy Plate Microalloyed with VN

Li Nan, Yang Caifu, Zhang Yongquan, Su Hang

2007, 28(2): 27-32,42.

Abstract(19) PDF(1)

Abstract:
During hot rolling of heavy plate,deformation inhomogeneity along the thickness direction will lead to the inhomogeneity of microstructure and mechanical properties.Therefore it is very important to choose a suitable rolling schedule.To investigate the effect of rolling schedule on the microstructure and mechanical properties of plate,finite element method (FEM) was used to simulate the rolling process of 50 mm thick plate.And the deformation at different position of the plate was obtained.Combining the simulation results with Gleeble physical simulation,the effect of rolling schedule on the section effect of VN microalloyed heavy plate was studied.The results indicate that the best section homogeneity can be obtained when the plate was given heat preservation after final rolled at 870℃.

Dissolve Rule of Nb,V,Ti in Microalloyed Steel

Cui Yi, Zhang Pengcheng, Tang Di, Huang Guojian

2007, 28(2): 33-36,42.

Abstract(20) PDF(1)

Abstract:
With the aid of extraction complex of C thin film,TEM and energy dispersion X-ray spectrum (EDX),the dissolve rule of Nb,V and Ti in Nb-V-Ti and V-Ti microalloyed steel was studied by isothermal holding at different temperatures and for different time.The results show that the large precipitate which is Ti-rich with a little Nb and V precipitate in solidification and form complex (Nb,V,Ti)(C,N) precipitate.The dissolution of V in V-Ti microalloyed steel is restrained by Ti.

Development of 800 MPa Low Yield Ratio Heavy Plate with Dual Phase

Yao Liandeng, Jiao Shengli, Zhao Xiaoting

2007, 28(2): 37-42.

Abstract(12) PDF(1)

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Through varying rolling and cooling parameter of Fe-0.1C-Mn-Mo microalloy steel,the dual phase structure of ferrite and martensite is obtained.The effect of process parameters on structure morphology,yield ratio,notch impact energy,elongation of the steel is discussed.The results show that changing rolling and cooling process parameter can realize the individuation control for strength,plasticity and yield ratio.The 800 MPa yield strength heavy plate with below 0.75 yield ratio has good low-temperature impact toughness,and the structure of the steel mainly consists of ferrite and martensite.

Investigation on Improving Combustion Properties of Blast Furnace Pulverized Coal Injection

Du Sihong

2007, 28(2): 43-47.

Abstract(19) PDF(1)

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To improve the combustion properties of blast furnace pulverized anthracite injection,a series of technical measures are tested in laboratory,which include add soft coal and combustion-supporting substance into anthracite,oxygen-enriched blast,enhance wind temperature etc.The results show every measure can improve the combustion properties,the effect of oxygen-enriched blast is especially notable.Injecting blended pulverized coal combined with oxygen-enriched blast and enhancing wind temperature can notably improve the combustion properties of blast furnace pulverized anthracite injection.

Effect of Magnesium Alloy on Deoxidation and Desulphurization of Molten Steel

Li Shangbing, Wang Qian, He Shengping

2007, 28(2): 74-77.

Abstract(19) PDF(1)

Abstract:
The deoxidation behavior of magnesium alloy in low carbon steel was investigated in a MgO crucible of induction furnace.The deoxidation effect of AlMg,SiCaBaMg,SiCaBaAlMg and Al as deoxidizer was compared in the experiment,and the change of T[O],[S] and inclusion content in the steel during the course of deoxidization was researched.The results show that the deoxidizing capability of SiCaBaAlMg and AlMg 1# is better than that of Al.The magnesium alloy also has good desulphurizing capability during the course of deoxidization,and the grain size of the deoxidization inclusion is fined.

Preparing Titanium Tetrachloride by Carbochlorinating Panzhihuan Titanium Slag with Combined Fluidized Bed

Yang Ping, Chen Deming

2007, 28(2): 48-52,73.

Abstract(25) PDF(1)

Abstract:
To prepare titanium tetrachloride,Panzhihuan titanium slag containing high calcium oxide and magnesium oxide is carbochlorinated in a combined fluidized bed reactor.The stickiness resistance of the reactor and the chlorination capability of Panzhihuan titanium slag are tested under hot reaction conditions.The experimental results show that combined fluidized bed is of good stickiness resistance in the presence of calcium chloride and magnesium chloride.The production capacity of the reactor for titanium tetrachloride is up to 38~76 t/(m²·d),which is 1~3 times of that of conventional fluidized bed reactor.

Preparing Monophase VO₂ Thin Film and Examining Its Microstructure

Qiao Wei, Li Zhidong, Zhao Kunyu, Li Linde, Meng Zhaobiao

2007, 28(2): 53-56.

Abstract(15) PDF(1)

Abstract:
The VO₂ thin film was made form V₂O₅ dry gelatin film by two-step annealing practice.The V₂O₅ gelatin film was prepared by inorganic sol-gel method from V₂O₄ powder and was dried in first annealing operation,then,the dry V₂O₅ film was annealed in vacuum quartz pipe at 450℃ and 480℃ respectively,so the VO₂ thin film was obtained.The microstructure of VO₂ thin film was examined by XRD and photomicrography.The results show the VO₂ thin film is monophase and annealing temperature has marked influence on the microstructure.

Development of Slag Brick with High Content of Ti-bearing Slag

Ao Jinqing, Hao Jianzhang, Wang Huaibin, Cao Zhiwei

2007, 28(2): 57-62.

Abstract(26) PDF(1)

Abstract:
Support vector machine is used for establishing the mathematical model of compositions and the cold crushing strength of the grounded Ti-bearing slag cementing material.With its application,the slag brick with over 80% Ti-bearing BF slag has been prepared which strength is up to MU15.The preparation of slag brick could be a new method for optimizing compositions of the slag cementing material and the mathematical model is a useful tool to the material design for utilization of high Ti-bearing slag.

Preparation and Photocatalytic Activity of Neutral La-TiO₂ Sol

Zhang Wenbin

2007, 28(2): 63-66.

Abstract(19) PDF(1)

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Neutral TiO₂ sol is prepared with H₂TiO₃ as raw material through hydrolysis,growth of crystal lattice and crystallization in low temperature.The sol is characterized by XRD,SEM,TEM,absorption spectrometry and so on.The results show that the diameter of La-TiO₂ is about 11.6 nm and the absorption edges of La-TiO₂ sol shifts to 545 nm.The La-TiO₂ sol has good photocatalytic activity for formaldehyde since wet-electron states come into form at interfaces of nanometer TiO₂ and H₂O molecules layer,however this photocatalytic performance is deeply affected by environmental humidity.

Research Progress in Direct Reduction of TiO₂ to Titanium

Wu Xiaosong, Lan Xinzhe, Zhao Xicheng, Wang Bixia, Cui Jingtao

2007, 28(2): 67-73.

Abstract(31) PDF(1)

Abstract:
A series of direct reduction process of TiO₂ to Ti was introduced based on the calciothermic reduction of TiO₂ power in molten CaCl₂ salt during electrolysis,which include FFC process developed by Cambridge University,OS process developed by Ono and Suzuki,metal thermal reduction process of TiO₂ developed by Park researchers combined the electronically mediated reaction (EMR) and molten salt electrolysis (MSE),and the preform reduction process (PRP) put forward by Okabe.The development in China of the direct reduction of titanium dioxide to titanium was introduced and the technical keys were discussed.It's concluded that the Cambridge's FFC process has the potential to replace the conventional Kroll process.

2007, 28(2): 78-82.

Abstract(21) PDF(1)

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2007 Vol. 28, No. 2